11:31 AM EST 1/31 - FINAL SCENARIO DECISIONS - As many are expecting, we are finalizing the projections for this event to the following main ideas. A precip/snow/timing map will be in progress today for issuance tonight. An early synopsis below, with additional detail this afternoon ahead of the map:OPTION A-- newly titled as "You The One I Want" is lowered to 30% but kept to account for an unexpected southward push of the cold front on Sunday night. There is a lot more precip with this system than the busted Round 1 of January 26-27, and that could lead to a surprise outcome for some if Snowstradamus played his wild card option below. Thanks to reader Kristin N. for capturing the feeling many Powderhounds have, we know you really wanted a good raging snowstorm (unless you are an outdoor worker.)

THE WILDCARD: Were the cold front to suddenly push south like it did early Monday 1/26, millions of us would end up in a very serious surprise snow and ice situation. The rising NAO forecast says otherwise, but large scale models have been known to be "off slightly" from time to time.

OPTION B -- newly titled as "So Close, So Close And Yet So Far" is raised to 70%. This looks to be the more probable outcome, as the track of the Low in Kansas (still about 1,500 miles away) would on Sunday traverse the mid-Mississippi Valley and reach northern Virginia by 7 PM Sunday. You can even detect the northward shifting on radar while the system is still way out there.

This track favors light snow for northern VA, MD and PA Sunday late morning to early afternoon - but the major cities from Philly to Baltimore to DC would change over to rain Sunday evening. Even northern and western counties would see precip fighting between snow and rain, with occasional mix overnight. The rain/snow line could even set up along near PA/MD line and create a sharp gradient with rain in Timonium and Bel Air MD, but heavy wet snow in Taneytown, Carroll County MD and Frederick MD.

Thanks to reader Mark M. for proposing this one last night. It could be tied to either the Hall & Oates classic or Elvis' timeless Paradise, depending on your music genre.

SUBMIT YOUR FUSION HEADLINE...

There's a lot of winter left. "That month" starts tomorrow. Many opportunities are left for fun headlines to come, with very worthy prizes from the team such as hoodies, beanies or perhaps your own FF snow ruler with the snowflake logo. If you have an idea for a future headline, such as good news on the weather horizon, a looming storm, a surprise ice storm, a light fluffy snow, or just a pleasant Spring day. We've seen it all in these parts and there's lyrics or quotes aplenty to match the varied weather of the East, only limitation is your boundless creativity!As the Carpenters might say, "It has only just begun" for we plan several more fun contests and powderhound prizes for readers here... from the seasoned pre-Facebook ones to the recent FB converts. More details on our next contest after the Sunday event.

"Til we find our place, on the path unwinding."-Circle of Life lyrics by Elton John in Soundtrack of The Lion King (Music video)

SCENARIOS AND ANALYSIS FOR SUNDAY-MONDAY EVENT FROM SOUTHEAST TO MID-ATLANTIC & NORTHEAST

12:15 PM EST 1/30 - UPDATED SCENARIO OVERVIEW - After a morning collaboration among members of the Winter Stormcast team in several states, we are posting revisions to our scenarios for the Sunday-Monday storm potential. This update is to account for new information received in the past 12-18 hours and reflect that insight in our projections.

Previous scenarios and map are still available in the lower section of the post for review.

SCENARIO A - The Powderhound favorite of "Big Kahuna"as shown below, has been reduced in probability from 50% to 40%. Large scale indications point to a more northerly track of the Low, and this outcome would hamper the chance for a significant snow event in the major metro areas.

One of many tell-tale signs for why we think this system will NOT become a "Big Kahuna" is an expected rapid rise in the North Atlantic Oscillation. Long-time readers know this is a large scale teleconnection we have used in previous winter storm forecasting. It was this and other techniques which tipped us off to why the Dec 19-20, 2009 blizzard would not stay to our south, but also why this weekend's storm looks to trend much farther north than what is shown in Scenario A below.

SCENARIO B - Called the "Little Bachata"depicts a light snow event in the MId-Atlantic with rain in the Carolinas as the system quickly moves out to sea. This was reduced in probability from 35% to 20%.

SCENARIO C - Dubbed "The Circle of Ice"is being modified to better specify what areas may be likely to see precipitation starting as frozen (snow, sleet, freezing rain), and which areas might stay primarily rain. The probability of this outcome has been raised from 15% to 40%.

WHEN WILL WE KNOW MORE? On Saturday, we anticipate narrowing this setup down to the two most probable forecasts, and then zeroing in on timing and impacts for each based on our examination of model projections blended by a healthy serving of "probability-based, ground truthed, common sense forecasting."

JUST CONSIDER...that given this system may have relatively higher liquid potential in these configurations. Even a quick hit from any of these scenarios with a lot of liquid converting to frozen precipitation can still be disruptive. We also invite you to review these resources at the NOAA Weather Prediction Center (WPC) for comparison:

1:10 PM 1/29 - Another Icy Surprise? We hope not, but atmospheric forces and ground temperature may have a different plan.

Our analysis of the enclosed image from the NOAA Storm Prediction Center indicates there is rising potential for a more widespread wintry mix event this afternoon across the region than may be expected.

A fast-moving cold front is forcing a notable amount of moisture ahead of it. This moisture will be moving into a stubborn surface layer of cold air with ground temperatures at or below freezing.

This may result in snow and sleet during the PM commute, starting between 3-4 PM in Frederick and Carroll County, moving to the Baltimore Metro areas between 4-5 PM, and tapering after 7 PM.

Since a surprise ice event on Sunday 1/18 was produced by less than one-TENTH of an inch of ice (0.10"), this heightens concerns for areas along the I-95 corridor on west, especially for any untreated roads.

Wednesday, January 28, 2015

A weekly forecast-in-jest from 2012 by our Western U.S. Coordinator Mark Ingalls, using humor to point out although history show the certainty that objects have struck Earth, and will again, on any given day there is a very low probability of that actually taking place.

2:05 PM EST 1/28 - With bright, cold sunshine returning to storm weary readers across the Eastern U.S., we take a moment to convey our deep appreciation and gratitude for the tremendous support you all have provided our teamthis winter and in the previous ten stretching back to January 26, 2004.

We appreciate and are thankful for the generous, insightful and thought-provoking feedback submitted in our previous post regarding the January 26-27 storm forecast and the weather politics that followed it.

If you are looking for the forecast, look below for details, except today it is presented as part lesson, part prediction as a learning exercise.

At end of the post, for those who have the patience to read and digest the content here, we reward you with a really funny, situationally appropriate video

Tuesday, January 27, 2015

A screen capture of the publicly available Surface Map Projection for 7 AM Monday morning

which is prepared at NOAA by a blend of forecast data and adjustment by Meteorologists.

The dark blue areas projected "Snow Likely" for a large portion of the Mid-Atlantic.

So what went wrong?

12:57 PM EST 1/27 - REQUEST FOR INPUT & EVALUATIVE COMMENTS ON STORM

Please read the following statement from a media outlet, and then guess what year it was written. Then click on the link at end to find out.

"Friday and Saturday A model designed to forecast coastal weather predicts that a storm from the Great Lakes will merge with the Atlantic low-pressure system off the coasts of Delaware and New Jersey. The model projects the storm will stall and dump as much as 28 inches of snow on New York City. Forecasters, including the National Weather Service, AccuWeather and local TV and radio meteorologists, warn of a blizzard in the city."

As we warned last night, Part 1 of this event fizzled today with the clipper system moving through. Now, a strong cyclone is starting to develop offshore, and this will begin phase 2 of this extremely complex system.

But before you ask, no, we will not get the big snow that parts of New England are projected to get. Beyond that, there is still some uncertainty because this storm is so complicated.

The graphic attached shows the total liquid precipitation from the late afternoon run of the HRRR (High Resolution Rapid Refresh) model - a very short range model sometimes useful for short term forecasting. This shows generally 0.1-0.3" of liquid this evening for the Mid-Atlantic region until early Tuesday morning.

EXPECTATIONS OVERNIGHT

Phase 2 does not look impressive, but it could cause more of an impact because of the lack of sunlight allowing accumulation on roadways.

That amount of liquid would translate to a total of about 1-3" of additional snow ending tonight using a 10:1 ratio.

This would be associated with a band of snow on the back edge of the developing cyclone retrograding from NE to SW across central MD this evening.

The biggest issue heading into the AM commute will be ICE! Moisture and standing water from snowmelt will refreeze overnight, especially on untreated and elevated surfaces.

BUST FOR PART 2 ALSO?

If this band does not form as indicated on this model (40% chance), most areas will be stuck with the coating-1" we got during the day today and that will be the end of it.

HEAVIER BANDS EXPECTED TO FORM OVER DELMARVA AND I-95 CORRIDOR AFTER 6 PM AS COASTAL HUGS DELAWARE AND JERSEY COAST TONIGHT.

10:15 AM 1/26 - UPDATE FROM THE WINTER STORMCAST TEAM1) Easterly flow has established across the southern Mid-Atlantic while the front that was stalled earlier in central PA moved south past 12 hours. National Weather Service has extended advisories in MD and VA southward to account for likelihood of wintry precipitation impacting area farther south than first expected.

2) The enclosed surface streamline map shows easterly flow has setup across almost the entire state. This is bringing moist Atlantic air west across Delmarva and over the Bay into the western shore. This is also evidenced on your local radar with snow filling in east to west.

3) With the coastal taking a while to get underway, this easterly flow in place, and energy transfer slow from the primary lows in Virginia, we expect a light steady snow to be the rule of the day for much of the state. Roads may stay wet in eastern counties, but could become snow covered in western counties as they are in the colder sector to the north of the Low.

Latest NOAA liquid projections show 0.50" or more for southern I-95 corridor, in excess of 1.00" for metro areas to New York City and into most of New England

6:30 AM 1/25 - UPDATED STATEMENT IN PROGRESS

With the NWS Advisory Map lighting up overnight straight to Maine, the "Boom" scenario is becoming more probable as a faster arrival of the clipper into the Mid-Atlantic with a faster development of the coastal Low puts the I-95 corridor under an increased risk of seeing 4 or more inches of snow.

The projected surface map for 7 PM tonight displayed left shows the situation becoming a battle for control of the "Route 30" corridor between a southward pressing Arctic High and the Low developing underneath as it slides East.A HYBRID CLIPPER AND A SCHEMING ARCTIC HIGH:

Unlike traditional clippers that just swing through unimpeded by a High pressure system to the north, this one has to battle for control of the map as it moves East.

This will enhance Easterly flow ahead of the system while the High delivers cold Arctic air, creating an ideal arrangement for snow,

The outcome will be a tale of two different storms. The west to east clipper will eventually deliver it's energy to, and form a secondary coastal Low that should turn the corner and head north, bringing heavy snow to the northeast corridor.

We think the cards are not yet all played, though. Southward pressing Highs like this can play a steady quiet hand through the round, then shoot the moon when you least expect it. Areas south of Baltimore and on the Eastern shore should stay alert for a changing forecast if this High tries to drop that Queen of Spades.

11:00 PM 1/24 - WSC TEAM ADVISOR'S STATEMENT

Before everyone takes off into snowfall projection land for this next event, there is an important weather concern our Advisors and Senior Forecasters wish to bring forward. This message was also shared with our partners, clients and Powderhound Insider subscribers.

BOOM OR BUST? We believe there is both an increasing probability of a blockbuster event, AND an equally strong chance for a major bust. We have seen this kind of setup before, and we've seen the negative reaction from readers when a big forecast goes belly us. Here's the issue:

"Clipper to Coastal" type energy transfer forecasts are fraught with peril. Sometimes they come together like a charm, other times you are expecting 6"+ of snow, and get clouds.

A healthy and moisture laden clipper IS coming rapidly East from the northern Plains. A large coastal storm should develop on the heels of that clipper energy as it reaches the Atlantic.

However, the scenario concerning us is that the Baltimore-DC region will be whipped into a frenzy just like this last dud (which we also expected to be a significant snow/ice event too....). Winter Storm Warnings will fly, then the snow will come down in sheets. Then some school districts may may pre-emptively announce closures Sunday night thinking that being proactive is always better.

Then--- at 3 AM, it shuts off-- and, crickets. The supposed energy transfer from the clipper to the coastal occurs too late. The front end snow turns out to be much less than we thought (when does that ever happen?) and there's a 12 hour window which was supposed to be all snow, and ends up as all nothing. Crews begin cleaning up, and viola! By 6 or 7 AM, many lots and roads are improving.

But Monday would be beyond salvaging. Businesses and schools would be already closed, when they could have squeaked out a 2-hour delay or modified hours. It is true several models are showing 0.60" or more for BWI airport, and that translates to 6-8" easily, but we've seen the models overproject on snow several times this winter.

This system is not a traditional coastal, nor is it a customary clipper. It's a clipper-to -hybrid-to-coastal, and it MIGHT become an example of our old rule: "Storms from the West don't bring extra rest." (If you work in or attend a school system.) For now, the one lesson we want to convey to all essential staff whose decisions impact their organizations:

This is one time we suggest you wait for ground truth to prove the forecast.

Don't pre-emptively close Sunday night just because it looks like a blizzard, even if there's a Winter Storm Warning. Just wait and see what conditions look like at 5 AM Monday. Maybe this time ground truth, or lack of it, is all the observations you will need to make the call.

You've been caught in the most desolate land in all of forecastdom: Land of the DRY SLOT! Consider if our payback to the weather for being sacked last Sunday morning.

NO, REALLY -- What happened? The system coming north didn't tap the nearby cold as quickly as expected. Given lack of a surface High with this system, there was skepticism about it from the start by some on our team.

Without the ability to really organize and pull in the colder components to our west, the eastern energy and precip generally separated.

Two small surface lows formed - one off the Delmarva - one over West Virginia. This shut off the precip in between, dumping you into the Land of the Dry Slot!

A simpler, non-scientific approach would be to glance out the window, observe little or no winter precip, and say, "Umm, I guess you were wrong??"

SO, WHAT'S NEXT? Snow is still expected this afternoon and early evening, but is not likely to be on the scale first projected.

Temperatures are running 2-3 degrees above forecasted and the freezing line has moved into southern PA.

Given what we see in the short range models for Monday and beyond, that is A OK. Today may be one of those reverse surprises, where snow is falling at different times, but it doesn't negatively impact your schedule.

That said, the second system coming Sunday evening into Monday looks to be coming from the Land of the Big Kahuna. With temperatures for that event heading into the 20s overnight into Monday, the outcome is going to be a lot snowier than today. Dare we use that special word reserved for only "certain storms"? You know, the word starting with "S", with the letters -ignifican- and ending in "T".

LET THE FLAG LIFT YOUR BLUES! This weekend into Monday marks the start of our team's 11th anniversary celebration. We are very excited to formally announce the first ever "Maryland Flag-in-the-Foot" embroidered hoody!. (No worries to all our other Mid-Atlantic brethren... we haven't overlooked you. Those designs will be forthcoming.)

GET ORDER DETAILS AND PRICING TODAY with a simple message to our online store. Just email to store@footsforecast.orgYou'll get a no pressure message back in a few minutes outlining your options and links to the store page for more information.

Thanks to all our readers for being an integral part of authentic local weather with us these 11 exciting, stormy, powdery years!!

Currently we have a LARGE swath of precipitation moving across the Mid-Atlantic region and though this is mainly rain or sleet for most, you should see a switch-over to snow as the night progresses!

As our team indicated in our forecast maps earlier, and posted below, several inches of snow and sleet could accumulate from this storm across the region by the time it finishes passing though tomorrow night. And, if you get the chance, we welcome your storm photos submitted to our Facebook pages anytime! Until there's enough snow to snap a photo, we invite your enjoyment of another favorite Enya tune of the team Powderhounds, "Amid the falling snow."

4:20 PM 1/22 - SCENARIO UPDATE As the window before Winter Storm Watches or Advisories begins to close, we have been watching upper level dynamics (the real data), and model projections (the simulated future data.) What these two data sets tell us about the weekend storm so far is:

That strange placement of a cold front in SE Canada could be a game-changer, or a non-issue. Usually one looks for a High pressure to settle in that location (if a snowy coastal event is desired.) However...

This storm is going to arrive at one of the climatologically coldest periods-- toward late January. Other computer models are indicating the storm could rapidly intensify once north of the Virginia capes.

This could in turn lead to "dynamical cooling" where the storm begins to manufacture it's own supply of cold air. The most notable example of this in recent years is the October 2011 "Shocktober Snow" -- which also lacked a surface High in the usual favored spot.

6:30 PM EST 1/20 - Our Winter Stormcast Team has been tracking the approach of a fast-moving Alberta Clipper now entering the northern Great Lakes area today. This system is expected to impact the upper Ohio Valley tonight and cross the Mid-Atlantic on Wednesday. A timeline of effects in the eastern states:

Overnight into Wednesday, snow will move into western Maryland and southern Pennsylvania.

By daybreak Wednesday, expect snow showers in the I-81 to I-95 corridors, reaching the Eastern shore toward end of the morning commute.

7:30 PM 1/14 - As temperatures resume a plunge back to the 20s overnight, we know thoughts in this post-storm period naturally turn to several questions about winter for many:

1) WAS THAT IT?2) WILL THERE BE A THAW?3) WHEN DO STORMS RETURN?

We will answer those questions in due time as we evaluate what scenarios are most probable in the next Long Range pattern. But first, there are some people who deserve time in the spotlight.

Photo credit: The London Times Online

This week, Mother Nature tried her best to throw another wintry trick. Even though forecasts were for marginal accumulations, and the reality bore that out for most locations in the Mid-Atlantic, a couple thousand people went forward with their duties anyway. Whether the atmosphere delivers one inch or twelve inches, they have a job to do. And did they ever do it this week.

We are talking about the many unsung heroes of winter weather management. These are the transportation workers, road crews, snow plow operators, emergency response teams and school officials. It's easy to overlook them, because they're out when you aren't, behind the wheel of a huge vehicle, or working in an deserted parking lot. But one observation is accurate no matter the location: They are the true winter knights of our time.

While we fret about snow ratios, which computer model is constipated or how upper level temperatures are uncooperative... down at the surface where real life is, it's moving forward because of these people. They put their lives aside, and leave their families for extended periods to engage in a hazardous endeavor when weather is at its worst. All this so we can drive to work or school, in relative comfort, with the least amount of interference possible.

Even if snow is a no-show, they still have to put in the time -- and there's not much thanks that goes around afterwards. The public moves on, the TV station stories return to non-weather topics, and the plows are put back until next time. There is one thing missing: Appreciation. For them, from us.If you see, or know, a transportation worker, school bus driver or plow operator, take a moment to offer your thanks for what they do. It might seem a small gesture, but it'll mean the world to them. It shows that their effort ARE appreciated, even when things go WELL, not just when it doesn't.From all of us at Foot's Forecast - we salute the real winter knights out there. We hope the next 10 days provides you welcome rest, before the next round returns.

We have been tracking an upper level shortwave moving northeast from the Gulf of Mexico, using some "old time techniques" that might be unfamiliar to even today's meteorologists. This approach suggested even yesterday the situation for Wednesday might not turn out as low impact as some currently expect.

Some computer models and short range maps at the NOAA Weather Prediction Center have been depicting an interaction between this shortwave, energy embedded under the High pressure, and a surface coastal system developing off the Carolinas.

What is going ON here? We think three factors are in play:

1) On-shore flow from the Atlantic courtesy of the northern High shown in this map will moisten the eastern Mid-Atlantic tonight into Wednesday.

2) Influence of the upper level short wave may enhance this moisture and touch off snow in areas that DO NOT AT ALL expect there to be more than flurries. Where? How about DC metro, southern Baltimore and the Chesapeake Bay.

3) Very cold air at the surface and upper levels would convert this moisture into snow, right quick, with rather high ratios if 5,000 foot temperatures will be between -10 C and -20 C tonight over these regions.

If you or someone you know is in charge of transportation duties for large organizations in these areas, might want to start checking the National Weather Service forecast in your area -- just so there's no surprises! We will have additional details on this potential system later this evening.